Shampoo Vs. Conditioner: Which Always Runs Out First?

Here we go again. I just tossed an empty bottle of conditioner into the recycle bin, leaving behind its matching bottle of shampoo, which remains 1/3 full. That bottle joins two other 1/3-full bottles of shampoo on my shower shelf. I can't bring myself to toss them, but I never seem to manage to use them up once I introduce a new matching shampoo-conditioner set I am all jazzed to try.

Am I the only one with a proliferation of partially fully shampoo bottles in her shower? I apparently use much more conditioner, so that always runs out much sooner than its mate. I can imagine that some people might use less conditioner than me, though, as my hair's so long.

This should make a fun poll. Let's see which usually runs out first: the conditioner or the shampoo.

After you vote, tell me: Do you manage to use up the bottle that's left behind, or does it linger on your shower shelf forever? Do you always buy the same kind of shampoo and conditioner to simplify the rotation process?